// Copyright (c) 2025 PaddlePaddle Authors. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include <stdio.h>
#include <string.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <sys/types.h>
#include "paddle/extension.h"

#ifndef PD_BUILD_STATIC_OP
#define PD_BUILD_STATIC_OP(name) PD_BUILD_OP(static_op_##name)
#endif

#define MAX_BSZ 128
#define K 5
// #define SAVE_WITH_OUTPUT_DEBUG

struct msgdata {
  long mtype;
  int mtext[MAX_BSZ * (K + 1) + 2];  // stop_flag, bsz, tokens
  float mtext_f[MAX_BSZ * (K + 1)];  // score
  int mtext_ranks[MAX_BSZ];          // ranks
};

void SaveOutMmsgTopK(const paddle::Tensor& x,
                     const paddle::Tensor& logprob_token_ids,  // [bsz, k+1]
                     const paddle::Tensor& logprob_scores,     // [bsz, k+1]
                     const paddle::Tensor& ranks,
                     const paddle::Tensor& not_need_stop,
                     int64_t rank_id) {
  if (rank_id > 0) {
    return;
  }
  auto x_cpu = x.copy_to(paddle::CPUPlace(), false);
  auto logprob_token_ids_cpu =
      logprob_token_ids.copy_to(paddle::CPUPlace(), false);
  auto logprob_scores_cpu = logprob_scores.copy_to(paddle::CPUPlace(), false);
  auto ranks_cpu = ranks.copy_to(paddle::CPUPlace(), false);
  int64_t* x_data = x_cpu.data<int64_t>();
  int64_t* logprob_token_ids_data = logprob_token_ids_cpu.data<int64_t>();
  float* logprob_scores_data = logprob_scores_cpu.data<float>();
  int64_t* ranks_data = ranks_cpu.data<int64_t>();
  static struct msgdata msg_sed;
  int msg_queue_id = 1;
  if (const char* inference_msg_queue_id_env_p =
          std::getenv("INFERENCE_MSG_QUEUE_ID")) {
    std::string inference_msg_queue_id_env_str(inference_msg_queue_id_env_p);
    int inference_msg_queue_id_from_env =
        std::stoi(inference_msg_queue_id_env_str);
    msg_queue_id = inference_msg_queue_id_from_env;
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Your INFERENCE_MSG_QUEUE_ID is: "
              << inference_msg_queue_id_from_env << std::endl;
#endif
  } else {
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Failed to got INFERENCE_MSG_QUEUE_ID at env, use default."
              << std::endl;
#endif
  }
  int inference_msg_id_from_env = 1;
  if (const char* inference_msg_id_env_p = std::getenv("INFERENCE_MSG_ID")) {
    std::string inference_msg_id_env_str(inference_msg_id_env_p);
    inference_msg_id_from_env = std::stoi(inference_msg_id_env_str);
    if (inference_msg_id_from_env == 2) {
      // 2 and -2 is preserve for no-output indication.
      throw std::runtime_error(
          " INFERENCE_MSG_ID cannot be 2, please use other number.");
    }
    if (inference_msg_id_from_env < 0) {
      throw std::runtime_error(
          " INFERENCE_MSG_ID cannot be negative, please use other "
          "number.");
    }
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Your INFERENCE_MSG_ID is: " << inference_msg_id_from_env
              << std::endl;
#endif
  } else {
#ifdef SAVE_WITH_OUTPUT_DEBUG
    std::cout << "Failed to got INFERENCE_MSG_ID at env, use (int)1 as default."
              << std::endl;
#endif
  }
  static key_t key = ftok("/dev/shm", msg_queue_id);
  static int msgid = msgget(key, IPC_CREAT | 0666);
#ifdef SAVE_WITH_OUTPUT_DEBUG
  std::cout << "save_output_key: " << key << std::endl;
  std::cout << "save msgid: " << msgid << std::endl;
#endif
  msg_sed.mtype = 1;
  bool not_need_stop_data = not_need_stop.data<bool>()[0];
  msg_sed.mtext[0] = not_need_stop_data ? inference_msg_id_from_env
                                        : -inference_msg_id_from_env;
  int bsz = x.shape()[0];
  int max_num_logprobs = logprob_token_ids.shape()[1];
  msg_sed.mtext[1] = bsz;
  for (int i = 0; i < bsz; i++) {
    for (int j = 0; j < K + 1; j++) {
      const int64_t offset = i * (K + 1) + j;
      if (j == 0) {
        msg_sed.mtext[offset + 2] = (int)x_data[i];
        msg_sed.mtext_f[offset] = logprob_scores_data[i * max_num_logprobs + j];
      } else if (j < max_num_logprobs) {
        msg_sed.mtext[offset + 2] =
            (int)logprob_token_ids_data[i * max_num_logprobs + j];
        msg_sed.mtext_f[offset] = logprob_scores_data[i * max_num_logprobs + j];
      } else {
        msg_sed.mtext[offset + 2] = -1;
        msg_sed.mtext_f[offset] = 0.0;
      }
    }
    msg_sed.mtext_ranks[i] = (int)ranks_data[i];
  }
#ifdef SAVE_WITH_OUTPUT_DEBUG
  std::cout << "msg data: ";
  for (int i = 0; i < bsz; i++) {
    std::cout << " " << (int)x_data[i];
  }
  std::cout << std::endl;
#endif

  size_t msg_len = (MAX_BSZ * (K + 1) + 2) * sizeof(int) +
                   (MAX_BSZ * (K + 1)) * sizeof(float) + MAX_BSZ * sizeof(int);

  if ((msgsnd(msgid, &msg_sed, msg_len, 0)) == -1) {
    printf("full msg buffer\n");
  }
  return;
}

PD_BUILD_STATIC_OP(save_output_topk)
    .Inputs({"x", "topk_ids", "logprob_scores", "ranks", "not_need_stop"})
    .Attrs({"rank_id: int64_t"})
    .Outputs({"x_out"})
    .SetInplaceMap({{"x", "x_out"}})
    .SetKernelFn(PD_KERNEL(SaveOutMmsgTopK));
